Efecto de técnicas de separación espermática en la viabilidad y estado acrosomal de espermatozoides posdescongelados de ovinos

Resumen

Se evaluó la efectividad de cuatro técnicas de separación espermática en semen descongelado de ovino. Se utilizaron 160 pajillas de 0.5 ml, con una concentración de 200X106/ml. En cada sesión de trabajo se descongelaron 4 pajillas a 37.5oC por 45 segundos, y se mezcló el contenido de ellas. Se tomaron 200 μl para realizar cada una de las siguientes técnicas: swim-up, Percoll, filtración a través de fibra de vidrio y filtración por Sephadex. La movilidad progresiva de los espermatozoides se incrementó en las pruebas obtenidas mediante swimup, fibra de vidrio y Sephadex (56.1%, 66.4% y 56.8%, respectivamente), con diferencia significativa (p< 0.05). Los espermatozoides vivos con reacción acrosomal se incrementaron en todas las técnicas de separación espermática, con una diferencia significativa (p<0.05) en los obtenidos con swim-up, fibra de vidrio y Sephadex, cuyos valores fueron superiores al 50.0%. Los espermatozoides muertos, con y sin reacción acrosomal, disminuyeron en todas las técnicas con excepción de los obtenidos mediante Percoll, en el que se observó una diferencia significativa (p<0.05) con relación al control, con excepción de los obtenidos mediante swim-up y Sephadex al evaluar los muertos con reacción acrosomal. Al evaluar los espermatozoides vivos sin RA, se encontró una disminución de este indicador en todos los tratamientos (13.1, 9.1, 9.3 y 10.8%, swim-up, Percoll, fibra de vidrio y Sephadex, respectivamente). La viabilidad espermática evaluada con la prueba hipoosmótica y Ioduro de propidio, determinaron que se obtienen un mayor porcentaje de espermatozoides vivos cuando son filtrados con fibra de vidrio (73.0% y 68.3%, prueba hipoosmótica e Ioduro de propidio, respectivamente); no se observa diferencia significativa (p>0.05) entre estas dos últimas pruebas.

Palabras clave: swim-up, técnicas de separación espermática, espermatozoides ovinos.

EFFECT OF SPERM SEPARATION TECHNIQUES ON THE VIABILITY AND ACROSOME REACTION OF FROZEN-THAWED OVINE SPERMATOZOIDS

ABSTRACT: The effectiveness of four sperm separation techniques on thawed ovine semen was evaluated. A hundred and sixty straws with 0.5 ml of semen with a concentration of 200x106/ml were used. In each work session, four straws were thawed at 37.5ºC for 45 sec mixing their contents. Then, 200 μl were taken to perform one of the following techniques: Swim-up, Percoll, filtering through glass fiber or filtering through Sephadex. Increased progressive motility of spermatozoids was obtained through swim-up, glass fiber and Sephadex (56.1%, 66.4%, and 56.8%, respectively), which was significantly different (p<0.05) in those recovered from glass fiber. The numbers of live spematozoids with acrosome reaction were high with all the separation techniques, with a significant difference (p<0.05) in those obtained from swim-up, glass fiber and Sephadex, whose values were higher than 50.0%. The numbers of dead spermatozoids, with and without acrosome reaction, were low in all the techniques, with the exception of those obtained by Percoll, which was significantly different (p<0.05) to the control, excepting those obtained by Sephadex and swim-up when the dead ones with acrosome reaction were evaluated. When evaluating live spermatozoids without acrosome reaction, a low value of this indicator was found in all the treatments (13.1, 9.1, 9.3 and 10.8%, swim-up, Percoll, glass fiber and Sephadex, respectively. The sperm viability evaluated with the hypo-osmotic test and propidium iodide concluded that a higher percentage of live spermatozoids were obtained when they were filtered with glass fiber (73.0% and 68.3%, hypo-osmotic test and propidium iodide, respectively); no significant differences (p<0.05) were observed between these two last test.

Key words: swim-up, sperm separation techniques, ovine spermatozoids.